1. Field
The present disclosure relates to inverters having a non-volatile memory function.
2. Description of the Related Art
Recently, as demand for portable information devices such as smart phones has rapidly increased, the development of non-volatile memory devices that are highly integrated, have small sizes, high speed, and high reliability has been considered. Also, in order to reduce a space occupied by a computer memory system, which includes logic circuits and a memory storage device, an attempt to load a memory function to an inverter has been tried.
As a non-volatile memory device, a polysilicon-oxide-nitride-oxide-silicon (SONOS) memory device compatible with manufacturing processes according to the prior art and having high performance memory characteristics has been considered as a next-generation non-volatile memory device. A tunneling insulation layer formed of a silicon oxide film in a single layer has a low operating speed and large power consumption when a thickness thereof is increased. However, if the thickness of the tunneling insulation layer is reduced to improve an operating speed, a direct tunneling phenomenon and a stress induced leakage current may increase.